In the manufacture of semiconductors a variety of highly corrosive chemicals, such as strong inorganic acids, strong inorganic bases, peroxides, and strong solvents, are used during an etching process to form the large number of signal traces or conduction paths that are contained in each semiconductor. In order to make the manufacturing process as efficient as possible, strong acids and bases are selected and then heated to decrease the amount of time required to complete the etching step. Accordingly, because of the extreme nature of the process chemicals and the operating conditions used in the semiconductor manufacturing industry, it is desirable that the fluid-handling devices involved in transporting such process chemicals be operated in a manner that insures that such potentially hazardous chemicals will not be released into the environment in the event of a failure of the fluid-handling device.
Additionally, the advance of technology has brought with it the need to electrically process information and perform functions at a quickened speed. Simultaneous with this need for quickened process time is the desire to keep the size of the electronic information processor down to a minimum. To achieve both of these features semiconductors are now designed to contain more process functions and features per unit size than previously available, i.e., increasing the component density of each semiconductor. One way that increased component density is achieved is by reducing the size of each component.
The extremely small scale of components used to construct semiconductor, and the need to further reduce the scale to enhance component density, has required the implementation of ever increasing quality control guidelines during the manufacturing process. The quality control guidelines have now progressed to the point where human operators are no longer allowed within the semiconductor manufacturing area because of the contamination risk from foreign objects such as dust, dirt and the like, that is associated with the presence of human operators.
Before these stringent quality control guidelines were implemented, human operators were routinely involved in the semiconductor manufacturing process. Accordingly, the leakage or failure of a fluid-transport device used in the manufacturing process could be visually detected by an operator. However, leak detection by operator observation was not the best method of detecting leakage or failure of the fluid-handling device due to inherent leakage of the process chemical into the environment. Liquid leakage was typically contained within a sump built around the perimeter of the fluid-handling device, posing a potential environmental hazard if not properly cleaned up, i.e., toxic vapors escaping to the atmosphere or toxic liquids leaking into the soil, and a potential health danger to operators working near the leak.
Accordingly, a need exists for an apparatus for sensing liquid leaking from a failed fluid-handling device that is capable of functioning without the need for operator presence or intervention. It is desirable that the leak-sensing apparatus be capable of detecting the leakage of liquid from a failed fluid-transport device in a manner that does not release the leaking liquid or vapor generated by the leaking fluid handling device to the environment, i.e., a closed system. It is desirable that the leak-sensing apparatus have the capability of detecting liquid leakage from more than one fluid-transport device, have a minimum number of moving parts to provide reliability, and be spatially efficient, i.e., occupy a relatively small space to promote its use in close areas. It is desirable that the leak-sensing apparatus be made from a material that is resistant to both the highly corrosive chemicals and temperature conditions that are used in the semiconductor manufacturing industry to ensure containment integrity of the leaking chemical and to reduce the possibility of process contamination. It is also desirable that the leak-sensing apparatus use a method of detection that is intrinsically safe and will not present an explosion hazard.